Lindsay Morris(NEW YORK) -- Since he was a toddler, PJ has liked pink and purple. But it wasn't until he started first grade, when the little boy drew a picture of himself in long hair and a dress, that his parents realized they had to be more proactive in dealing with his gender nonconformity.

"The first time it came up was when he was 2 1/2 in the shoe store," said his father, Timothy Snyder, 42. "He was running around refusing to take pink tennis shoes off his feet. In pre-school, we bought him some dress-up dresses and a nightgown."

"We didn't know how far the gender-bending would go," he said. "It crept into our lives."

Today, the 10-year-old from Jersey City, N.J., is comfortable in his skin, because Snyder says they have supported his choices. And for the past three summers, he has gone to a camp for like-minded boys.

PJ, the boy's initials because his parents want to protect his privacy, may never go on to identify as transgender. He adamantly tells his family and friends he is a boy.

"School has not been terrible, but it's definitely a challenge," said his father. "He has gotten some teasing and microteasing. Things like, 'Why do you wear your hair long?' and, 'I can't remember if you are a boy or a girl.'...It wears him down a bit. It causes issues with him -- he has a fairly strong wall built up, but he gets defensive and angry easily."

But now, PJ has a place free from bullying that has helped strengthen his self-esteem.

For four days in the summer, he joins other boys, some as young as 3, at a camp where they can express themselves as girls through high heels, make-up and lots of girly colors. Here, these gender-nonconforming children are given an opportunity to be free of judgment and able to express themselves creatively, perhaps openly, for the first time.

His parents and his siblings, aged 3 and 4, go along as well.

As boys like PJ, who seem to at first just experiment with being girls, get older, "it a little more complicated," said Snyder. Some, though not all, may go on to be transgender or gay.

The camp, begun by parents, is so informal that it moves from one part of the country to another, depending on where parents can rent space from retreat centers. Most have been run by religious groups.

The families that come are from all walks of life and some "really do struggle with acceptance at so many levels," Snyder said.

"These are not parents trying to make a political or social statement by any means, but rather a very personal family journey -- and sometimes struggle," he said.

"People talked about how wonderful the camp was and cathartic for so many families and kids, so we made it a priority to go," said Snyder, who is an IT specialist.

During the day, children tie-dye T-shirts and have outdoor activities. In the evening, there's a talent show in which campers can sing, dance or play piano. Another night is a pageant show in which the boys can dress up.

For the last three years, New York photographer Lindsay Morris has captured the children in images of their self-expression. She hopes to publish a book next year and would like to use any profits to jump start a foundation to support the camp.

Morris calls the camp, "You Are You," out of respect for families and their children and does not reveal where the images were taken.

"It's really just an opportunity for these kids to meet other children who are like themselves," said Morris, 47, and the mother of two children. "The whole idea is that these kids feel very alone in life."

And their parents are "pioneers," according to Morris.

Gender nonconforming or gender variant are terms for people whose gender expression differs from stereotypical expectations, such as "feminine" boys, "masculine" girls, and those who are perceived as androgynous. This includes people who identify outside traditional gender categories or identify as both genders. Many are bullied in school and may be isolated socially.

Jack Halberstam, professor of American and gender studies at University of Southern California, said society is as hard on girls who are gender variant as boys. Born female but identifying as male, he said "60 to 70 percent of my life," he was mistaken as a boy.

"It still has an impact," he said. "Kids who are not exactly conventional -- girls wearing boys' clothes and playing boys' games or people saying, 'What a cute boy you have' to parents. Whatever it may be, it has an impact. On top of that, adults have extreme discomfort with cross-identified children. It's a toxic brew for creating confusion for children."

"The little girl who says she is a tomboy or wants to wear jeans or play with boys is fine, but the minute a girl says, 'I like another girl and ... and I only want to wear boys' underwear, that means she becomes subject to the same kinds of policing scrutiny as boys," Halberstam added. "Little girls who cross the line aren't cute anymore."

Halberstam said that the total numbers of gender-nonconforming children are "more common than you might expect."

Getting exact numbers is challenging. Some specialists estimate that 1 in 500 children is significantly gender nonconforming or transgender, according to the education and advocacy group Gender Spectrum. An older study based on statistics of postoperative transgender men puts the number at 1 in 20,000.

Fewer than 700,000 Americans identify as transgender, according to the Williams Institute, a think tank at UCLA Law School, which researches issues that affect people who are lesbian, gay, bisexual and transgender.

Mara Keisling, executive director of the National Center for Transgender Equality, said that a camp like "You Are You" cannot push a child's gender identification in one direction or the other.

"You cannot turn kids gay and you cannot turn kids transgender," said Keisling. "That's utter nonsense and every expert in the country knows that. What you can do is make them better and stronger and more caring people by showing you are."

Some argue that gender identification is based on genetics. But one recent case seems to refute that.

Identical twins Wyatt and Jonas Maines share the same DNA, but their gender identification took divergent paths. As early as age 4, Wyatt asked his mother, "When do I get to be a girl?" And he told his father he hated his penis.

Now, at age 16, the twins, who are from Maine, are brother and sister. Wyatt is now Nicole, undergoing transition with hormone treatment at Gender Management Service at Children's Hospital in Boston.

The majority of all children who express the belief that they are the wrong gender will enter puberty and go on to identify with their biological gender, according to endocrinologist Dr. Norman Spack, who treats Nicole.

"Of all little kids who are gender variant, 20 percent will stick with it," he told ABCNews.com when the Maines story was first reported in 2011. "Over 80 percent will accept looking like Jonas and would push talk about cutting off [their penis.]"

The Rev. Stan Sloan, CEO of Chicago House, which provides some of the nation's most comprehensive services for transgender people, said gender variant children need encouragement and support.

"Ultimately, they become the people they were meant to be," he said. "Maybe a boy wants to wear pink for a year and moves on, or he's in love with pink and transitions -- or doesn't transition."

Sloan, who is gay, said, "If I could have known as a little kid there was a camp where little kids were gay and struggling with the same thing, it would have made such a difference....If it does nothing else, it gives [kids] a few weeks in what feels like a world that is accepting and understanding and doesn't pass judgment."

So far, some of the camp's alumni, when they reached puberty, went on hormone blockers to begin transition from boy to girl. Others have decided they are gay, according to Snyder.

"There are definitely a variety of possibilities. For most parents, it's hard to believe that their kid will turn out straight and gender-conforming," Snyder said. "But statistically, it's true that some of our kids will end up being gender nonconforming, but still conforming enough to be straight."

Snyder said a psychologist who is treating his son has advised the parents to allow the boy to freely express himself. But PJ's parents also consulted a psychiatrist this year because of some social and behavioral issues.

The Snyders said they are open-minded and live in a diverse neighborhood where their three children play with children of same-sex couples. But other parents have a harder time accepting their gender variant children.

"What really riles people...is they think that instantly you are forcing a child into being gay or lesbian or transsexual," he said. "It's not that at all. Our children really want to express a different gender identity and we have to be ready...because you just don't know."

But for now, his father said, the "quickest way" his 10-year-old explains himself to others is: "I know I have long hair and wear girls' clothes, but I am just a boy who happens to like pink and purple."

"When I asked, 'Well, what is it that makes you a boy versus a girl?' he came up with a cool answer," said his father: "I've got friends at school who really like soccer and wear T-shirts from professional soccer teams," PJ will say. "Just 'cause I wear a shirt doesn't make me a professional soccer player."